Multiple-blade disconnecting switch



Patented Sept. 26 1939 UNITED STATES PATENT OFFICE MULTIPLE-BLADEDISCONNECTING swrron Pennsylvania Application February 27, 193,7, SerialNo. 128,197

11 Claims.

The invention relates, in general, to electrical circuit controllingdevices, and more particularly, to multiple blade disconnecting switchesfor power distribution systems.

The increasing power requirements in electrical power distributionsystems had led to the use of double-channel type bus bars forconductors. This type of conductor approximates a tube ,or hollow squarein cross-section, and provides an extremely efficient conducting meansfor large alternating currents. The larger power require ments have alsogreatly increased the demand for heavy capacity switches.

, The heavy capacity switches that have heretor forebeen known or usedare not well adapted either for use with double-channel type bus bars orin large capacity power systems.

One objectionable feature of the prior art multipleblade switchstructures is that the arrangementof the blades results in an unevendistribution of the current flowing through the blades, particularly forhigh current values. If the crosssection of the blades is increased tomeet higher power requirements, the inner blades have'a much largercross-section than is necessary to carry the current flowing throughthem, resulting in wastage of copper and increased, production cost. Ifthe number of blades is increased to meet the higher power requirements,the width of the switch is greatly increased, which is highlyobjectionable.

Another objectionable feature of the prior art switch structures is thatthey are subject to being blown open by magnetic reaction when carryinghigh magnitude currents, and consequently, must be provided with lookingor latching means to hold the switch closed. The blow-out magneticreaction results from the fact that the current traverses a curved orangular path adjacent the switch jaws.

Another objectionable feature of the prior art switch structures is thatas their size or capacity is increased to meet the increased powerrequirements, the operating effort required to open and to close theswitch becomes considerably larger.

An object of the invention is the provision of a switch structureembodying an improved terminal and contact structure for connecting theswitch in an electrical circuit in such a manner that the current flowsin substantially a straight line through the switch.

Another object of the invention is the provision of a switch embodyingan improved terminal and. contact structure for connecting the: switchto doublech'annel type bus bars.

Another object of the invention is the provision of a disconnectingswitch embodying an improved integrally formed contact and terminalconnection for connecting the switch to double-channel type bus bars,which eliminates the necessity of separate insulating supports, underthe channel bus ends adjacent the switch terminals.

Another object of the invention is the provision of a multiple-bladedisconnecting switch in which the blades are arranged in the form of ahollow square grouped away from the center so as to produce an evendistribution of current flow through the blades, thus reducing thecopper section required and producing a compact switch structure.

Another object of the invention is the provision of a multiple-bladedisconnecting switch embodying an improved operating mechanism whichgreatly reduces the operating effort required to openand to close theswitch blades.

7 Another object of the invention is the provisionof a multiple-bladedisconnecting switch with an improved, operating mechanism for openingand ,closing the blades with a minimum operating effort, the mechanismbeing operable either during opening or closing of the switch to firstmove the blades which require the least effort, and then to move theremaining blades.

Another object of the invention is the provision of an improveddisconnecting switch that is reliable, efiicient, easy to operate, andinexpensive to manufacture. The novel features that are consideredcharacteristic of the invention are set forth in particular in theappended claims. The invention itself, however, both, as v.to structureand operation, together with additional objects and advantages thereof,will best be understood from the following detailed description of aspecific embodiment thereof when, readin connection with theaccompanying drawing, in which:

Figure l is a side elevational View of a multiple-blade disconnectingswitch embodying the features of the invention, the switch being shownin the closed circuit position;

Fig, 2 is an end elevational view of the switch shown in Fig. 1;

,Fig. 3 is a side elevational View of the switch similarto Fig. 1,showing the relative positions of the parts during the first part of theopening movement when the upper blades require less effort to open thanthelower blades;

Fig. 4 is aside elevational view of a portion .of the switch showing therelative positions of the blades. during the opening operation aninstant after the lower blades have left their stationary contacts;

Fig. 5 is a side elevational view of a portion of the switch showing therelative positions of the blades during a closing operation, when theupper pair of blades require less efiort to close;

Fig. 6 is a side elevational view of a portion of the switch showing therelative positions of the blades during a closing operation when thelower pair of blades require less effort to close; and

Fig. 7 is a vertical sectional View through the switch member taken onthe line VII-VII of Fig. 1.

Referring to the drawing, and particularly to Figs. 1 and 2 thereof, asingle pole multiple-blade disconnecting switch is illustratedcomprising a pair of supporting members I on which are mountedinsulating pillars 9 and II, the pillar 9 supporting a jaw member I3 andthe pillar I I supporting a jaw member I 5.

The jaw members I3 and I5 are substantially identical and each comprisesa U-shaped plate of conducting material having a bight portion I1 and apair of spaced parallel legs I9. The width of the plate is substantiallyequal to the distance between the legs I9. The end of each leg of thejaw member has the upper corner portion cut away so as to provide anupper contact portion or jaw 2| and a lower contact portion or jaw 23,the jaws ZI and 23 being disposed in the same vertical plane. The twolegs of the jaw member thus form four contacts or jaws, two lowercontacts or jaws 23 and two upper contacts or jaws 2|, for cooperatingwith a multiple-blade switch member 33 which will be describedhereinafter.

Each jaw member is supported on its insulator column by means of ametallic angle bracket 25, the bight portion I l of the jaw member beingsecured to. the vertical leg of the bracket 25 in any suitable manner.The horizontal leg of the bracket 25 is secured to the metal cap pieceof the insulator column and is provided with a pair of integral upwardlybent projections 21 which form supports for the legs I9 of the jawmember I3.

The portions of the legs I9 of the jaw member adjacent the bight portionI'I thereof form terminal connecting straps for mechanically andelectrically connecting the switch to the ends of a pair of bus bars 29.The bus bars illustrated are of the double-channel type, as more clearlyshown in Fig. 2, and the ends of the webs of each double-channel bus barare connected to the legs I9 of the jaw member by means of bolts 3I. Itwill thus be seen that the particular form of jaw members adapts theswitch for use with doublechannel type bus bars in which use the channelbus ends are connected directly to the jaw members, eliminating thenecessity of any additional insulating supports under the channel busends adjacent the switch jaws.

While the specific structure of the jaw members particularly adapts theswitch for use with double-channel type bus bars, it is to be understoodthat the jaw members also lend themselves to other types of connectionsand can be used to connect the switch to other types of bus bars orother types of conductors.

The multiple-blade switch member indicated generally at 33 comprises apair of lower double blade switch members 35 and a pair of upper doubleblade switch members 31. The lower pair of blade members 35 are pivotedto the lower pair of spaced contacts or jaws 23 of the hinge jaw memberI3 by means of a bolt 39, and the upper pair of blade members 31 arepivoted to the upper pair of spaced contacts or jaws 2I of the jawmember I3. The upper pair of blade members are similar to the lower pairof blade members except that they are of slightly greater length.

Each of the blade members of both the upper and lower pair comprises apair of blades 36 which are pivotally mounted on opposite sides of theircorresponding contact or jaw ZI or 23, as the case may be, by means ofthe bolt 39. The blades 36 are pressed firmly into engagement with theircontacts or jaw by means of conventional spring washers M in order toprovide good electrical contact between the blades and the contact orjaw. The blades 36 are spaced apart by spacer members 38 locatedintermediate the ends of the blades. The forward ends of the blades 36are yieldingly pressed toward one another and firmly against theircorresponding break contacts or jaws 2I or 23, as the case may be, ofthe contact jaw member I5 by means of similar spring washers 42 mountedin position on the outside of each of the blades by means of a bolt 43.

The blade members 35 and 3! of each pair are secured for movementtogether by means of the bolts 43 which extend transversely through theblade members and blades of each pair, the spring washers 42 being heldin position on the bolts by means of nuts.

Each of the contacts or jaws 2| and 23 of the contact jaw I5 is providedwith a slot 45 for receiving the bolts 43 which connect the blades andblade members of each pair. It will thus be seen that each pair of blademembers is mounted for swinging movement into and out of engagement withtheir corresponding contacts or jaws of the contact jaw member I5.

The pivots 39 of the blade members are so positioned that the blademembers are spaced equal distances from the central longitudinal axis ofthe switch member 33 so that in a transverse section through the switchmember 33 the blade members are arranged in the form of a hollow squareas is shown in Fig. '7.

This particular spacing of the blade members substantially equaldistances away from the central longitudinal axis of the switch membermakes use of the skin effect of the heavy alternating currents flowingthrough the switch to provide for a substantially equal distribution ofthe current flowing through the blade members, thus reducing coppersection and copper wastage. The arrangement of the blade members in thehollow square formation produces these desirable results withoutincreasing the width of the switch.

The specific structure of the jaw members coupled with the arrangementof the blades in alignment with the buses also provides a substantiallystraight-line path or paths for the current flowing through the switch,thus preventing any tendency of the switch member to blow open whencarrying heavy alternating currents and thus eliminating the necessityof providing any latching or locking means for the blade members to holdthem in closed circuit position.

In the prior art switch structures in which the terminal connectors werenot located in alignment with the contact jaws, it was necessary toprovide a latching means to hold the switch in closed position due tothe fact that the current in flowing through the switch traversed curvedpaths adjacent the jaw members and set up magnetic reactions whichtended to blow the switch open on heavy current values. The particularstructure'jof thjaw members in the present instance, in addition toadapting the switch for use with the double-channel type bus bars, alsoeliminates the development of any magnetic forces which would tend toblow the switch open.

As the size of the switch is increased, the operating effort requiredtoopen and close the switch also increases, and in heavy duty switches,the operating effort becomes extremely large. In the slwitch illustratedin the drawing, if the four blade members were all secured together forsimultaneous opening and closing, considerable operating force would berequired to operate the switch. In order to overcome this difficulty, anoperating means has been provided for the switch which considerablyreduces, the operating effort required to open and to close the switch.

The operating means comprises a motor driven crank arm 46, an operatingmember 41, a pair of links 49 pivotally connecting the operating memberto the lower pair of blade members 35, a link 5| connecting theoperating member to the upper pair of blade members 3'! and a lostmotion connecting means between the upper and lower pairs of blademembers comprising a pair of slotted links 53. The operating member 41is provided with a bifurcated end portion 55 for receiving the upperends of the links 49 and the link 5|. The upper ends of the links 49 andthe link 5| are pivotally secured to the bifurcated portion 55 of theoperating member 41' by means of a common transverse pivot pin 51. Theupper end of the operating member 41 is pivotally connected to the endof the motor driven crank arm 45 by means of a pivot pin 48. The lowerends of the links 49 are pivotally connected to the lower pair of blademembers by means of a transverse pivot pin 59, while the lower end ofthe link 5! is pivotally connected to the upper pair of blade members 31by means of a transverse pivot pin 6!. The pivot point 59 of the links49 and the pivot point 6| of the link 5| are located at differentdistances from the hinge jaw member l3, so that in side elevation, thelinks 49 and the link 5! form two sides of a triangle.

The lost motion connecting means comprises a pair of slotted links 53pivoted at their upper ends to the outer blades of the upper pair ofblade members 37 by means of pivot pins 63. The lower portions of thelinks 53 are provided with slots 65 and the outer blades of the lowerpair of blade members 35 are each provided with a projecting pivot pin6! which passes through the slot 65 in the corresponding link member 53.In the closed circuit position of the blade members, the pro jectingpivot pins 61 lie in the center portion of the slots 65, as shown inFig. 1. The slots 65 are of such length that the upper pair of blademembers 31 can be completely disengaged from their corresponding breakcontacts or jaws 2| before the lower ends of the slots 65 engage theprojecting pivot pins G'l of the lower pair of blade members 35, andlikewise, the lower pair of blade members 35 can be completelydisengaged from their corresponding contacts or jaws 23 before the pins61 engage the upper ends of the slots 65.

The operating means is operable during a circult opening operation tofirst completely disengage whichever pair of blade members requires theleast disengaging eifort, and then to pickup and disengage the remainingpair of blade members, and is operable during a closing operation tofirst completely close whichever pair of blade members requires theleast closing eifort and then to completely close the remaining pair ofblade members; To open the switch, the motor driving means (not shown)is operated to cause the crank arm 46 to exert a pull on the operatingmember 41 as indicated by the arrow in Fig. 3. The major portion of thepulling force exerted on the operating member 41 is transmitted by thelinkage to whichever pair of blade members require the least operatingeifort, so that these blade members are first completely disengaged fromtheir corresponding contacts or jaws.

In Fig. 3,. the relative position of the linkage and blade members isshown under the conditions when the upper pair of blade members 3!require the least disengaging effort. In this case, continued pull ontheoperating member 4'! causes the connecting links 53 to pick up or exertan opening force on the lower pair of blade members by reason of thefact that the projecting pins 67 carried by the lower pair of blademembers 35 have reached the ends of the slots 65 in the links 53. Atthis point the major portion of the force exerted on the operatingmember 41 is transmitted to the lower pair of blade members 35, andthese blade members are disengaged from their corresponding breakcontacts or jaws 23. Further pull on the operating member 41 swings bothpair of blade members to a substantially vertical open position.

If the lower pair of blade members require less disengaging effort thanthe upper pair of blade members, the pulling force on the operatingmember 47 is first transmitted by the linkage to the lower pair of blademembers 35. When these blade members have disengaged their correspondingbreak contacts or jaws 23, the projecting pins 6? will have engaged theupper ends of the slots 35 in the connecting links 53, so that continuedpull on the operating member 41 is then transmitted to the upper pair ofblade mem bers 31 to disengage the same from their corresponding breakcontacts or jaws 2!, After both pairs of blade members have beendisengaged from their corresponding contacts or jaws, the entire switchmember 33 is rotated in a counterclockwise direction to an open circuitposition away from the contact or break jaw member l5. At this point,the motor driving means becomes automatically deenergized in anyconventional manner.

To close the switch, the motor driving means is operated to cause thecrank arm 46 to exert a pushing force on the operating member 41. Duringthe first part of the closing operation, this pushing force swings bothpairs of blade members toward the contact jaw member l5 until the lowerpair of blade members 35 engage the top of their corresponding contactsor jaws 23 of the contact jaw member l5. At this point in the closingoperation the major portion of the pushing force is transmitted to theupper pair of blade members until they engage the top of theircorresponding contacts or jaws 2|. At this point, the major portion ofthe closing force is transmitted by the linkage to whichever pair ofblade members require the least closing effort to completely close thispair of blade members on their corresponding contacts.

In Fig. 5, the positions of the parts are shown under conditions whenthe upper pair of blade members required the least closing force. Inthis case, after the upper pair of blade members have been completelyclosed, as shown in Fig. 5, the major portion of the force istransmitted by the linkage to the lower pair of blade members 35 to'completely close the'same.

In Fig. 6, the positions of the parts are shown under the conditionswhen the lower pair of blade members 35 required the least closingforce. In this case after the lower pair of blade members 35 have beencompletely closed, the pushing force is then transferred by the linkageto the upper pair of blade members to completely close this pair. Afterboth pairs of blade members have been closed, the motor driving means isautomatically deenergized in any conventional manner.

It will thus be seen that the particular operating means by firstopening or closing, as the case may be, a part only of the blade membersmaterially reduces the operating effort required.

The invention provides an improved switch structure which is highlyefiicient, which is particularly well adapted for use with the populardouble-channel type bus bars, and which requires a minimum operatingefiort. The specific structure of the jaw members provides astraight-line path for the flow of current through the switch,eliminating the necessity for latching or locking means for the switchmember; particularly adapts the switch for connection with doublechanneltype bus bars in such a manner that they eliminate the necessity of anyadditional insulating supports for the bus ends adjacent the switchterminals. The spacing of the blade members in the form of a hollowsquare makes use of the skin effect of the heavy alternating currentsflowing through the switch to provide substantially even distribution ofthe current flowing through the blade members, thus reducing coppersection, eliminating waste and providing a compact switch structure thatcan be manufeatured at an extremely low cost. The novel operating meansmaterially reduces the operating efiort required to open and close theswitch.

While the invention has been shown and described in accordance with theprovisions of the patent statutes, it is to be understood that variouschanges in the structure may be made without departing from the spiritof the invention. I desire, therefore, that the invention be limitedonly by the reasonable construction of the appended claims and by theprior art.

I claim as my invention:

1. In an electric switch for use with doublechannel type bus bars, apair of spaced insulating supports, a U-shaped plate of conductingmaterial supported on each insulator, portions of the legs of saidplates forming terminal connecting straps for mechanically andelectrically connecting the switch to the bus bars, other portions ofsaid legs forming contact jaws, a movable switch member comprising aplurality of spaced switch blades pivoted to the contact jaws of one ofsaid plates for swinging movement into and out of engagement with thecontact jaws of the other plate, means for operating said switch memberto open or to close the circuit through said switch.

2. In an electric switch for use with doublechannel type bus bars, apair of spaced insulating supports, a U-shaped plate of conductingmaterial supported on each insulator, portions of the legs of saidplates forming terminal connecting straps for mechanically andelectrically connecting the switch to the bus bars, other portions ofsaid legs forming contact jaws, a movable switch member comprising aplurality of spaced switch blades pivoted to the contact jaws of one ofsaid plates for swinging movement into and out of engagement with thecontact jaws of the other plate, means for operating said switch memberto open or to close the circuit through said switch, said terminalconnecting straps, said contact jaws and said switch blades in theclosed position of said switch forming straight-line paths for thecurrent flowing through said switch.

3. In a multiple-blade electric switch, a pair of spaced insulatingsupports, a terminal means secured to each support, said terminal meanscomprising a member of conducting material provided with a plurality ofspaced contact jaws, a movable switch member comprising a plurality ofswitch blades pivoted to the contact jaws of one terminal means forswinging movement into and out of engagement with the correspondingcontact jaws of the other terminal means, said blades being spaced awayfrom the center longitudinal axis of said switch member in hollow squareformation to provide for substantially equal distribution of the currentflowing through said blades, and at the same time maintaining a minimumwidth dimension of said switch.

4. In a multiple-blade electric switch, a pair of spaced insulatingsupports, a terminal means secured to each support, said terminalcomprising a member of conducting material provided with a plurality ofintegral spaced contact jaws, a movable switch member comprising aplurality of switch blades pivoted to the contact jaws of one terminalmeans for swinging movement into and out of engagement with the contactjaws of the other terminal means, said blades being spaced away from thecenter longitudinal axis of said switch member in hollow squareformation to provide for substantially equal distribution of the currentflowing through said blades, and at the same time maintaining a minimumwidth dimension of said switch, said terminal means and said switchblades providing straightline paths for the current flowing through saidswitch.

5. In a multiple-blade disconnecting switch, a pair of spaced terminalmeans, each provided with a plurality of spaced contact jaws, a switchmember comprising a plurality of spaced switch blades pivoted to thecontact jaws of one of said terminal means for swinging movement intoand out of engagement with the contact jaws of said other terminalmeans, operating means for said switch member operable during a circuitclosing operation of the switch to first close whichever blades requirethe least closing effort and then to close the remaining blades, andoperable during a circuit opening operation to first begin to disengagefrom said contact jaws whichever blades require the least disengagingeffort and then to begin to disengage the remaining blades.

6. In a multiple-blade disconnecting switch, a pair of spaced jawcontact members, a plurality of switch blades pivoted to one of said jawconjaw contact member whichever blades require the least disengagingeffort, then to disengage the remaining blades from said jaw contactmember and then to swing all of said blades away from said jaw contactmember.

'7. In a multiple-blade switch, a pair of spaced contact means, a switchmember comprising a first blade means and a second blade means bothpivoted to one of said contact means for swinging movement into and outof engagement with said other contact means to close or open the circuitthrough said switch, operating means for said switch member comprising amovable operating member, a pair of links pivoted at their one end tosaid operating member, the other end of one of said links being pivotedto said first blade means and the other end of said other link beingpivoted to said second blade means, said lastmentioned pivots beinglocated at diiferent distances from said pivot contact means, a lostmotion connection between said first and second blade means, saidoperating means being operable during a closing operation for firstclosing whichever blade means requires the least closing effort and thenclosing the other blade means, and operable during an opening operationfor first beginning opening of Whichever blade means requires the leastopening effort and then opening the other blade means.

8. In a multi-blade switch, a pair of spaced terminals each having twopair of contacts, a movable switch member for bridging said terminalscomprising two pairs of switch blades separately pivoted about parallelaxes, one pair above the other, to the two pairs of contacts of one ofsaid terminals for swinging movement into and out of engagement with thetwo pairs of contacts of the other terminal, said contacts and bladesbeing each spaced an equal distance away from the central longitudinalaxis of the switch member so that the blades are arranged in hollowsquare formation to provide for substantially equal distribution of thecurent flowing through the switch.

9. In a multi-blade switch, a pair of spaced terminals each comprising apair of spaced par allel plates, portions of which form terminalconnecting straps to which conducting bus bars are adapted to besecured, other portions of said plates forming two pairs of contacts, amovable switch member for bridging said terminals comprising two pairsof switch blades pivoted to the two pairs of contacts of one terminal,one pair above the other, at four points equidistant from thelongitudinal center axis of the switch member, for swinging movementinto and out of engagement with the two pairs of contacts of the otherterminal, said plates and switch blades forming substantially straightline paths for the fiow of current through said switch.

10. In a multi-blade switch, a pair of spaced terminals each having aplurality of spaced contacts, a movable switch member for bridging said"terminals comprising a plurality of blade means engageable with saidcontacts, and operating means operable during opening of the switch tofirst begin to disengage from said contacts whichever blade meansrequires the least disengaging efiort and then to disengage theremaining blade means prior to moving the switch member to openposition.

11. In a multi-blade switch, a pair of spaced terminals each providedwith a plurality of spaced contacts, a switch member comprising aplurality of spaced switch blades pivoted to the contacts of one of saidterminals for swinging movement into and out of engagement with thecontacts of the other terminal, operating means for the switch memberoperable during a circuit opening operation to first begin to disengagefrom the break contacts whichever blades require the least disengagingeffort and then to begin to disengage the remaining blades.

HERBERT J. CRABBS.

